on the French frontier and compelled to take
out a license. During the war the cerium sparklers were much used in the
trenches for lighting cigarettes, but--as those who have seen "The
Better 'Ole" will know--they sometimes fail to strike fire. Auer-metal
or cerium-iron alloy was used in munitions to ignite hand grenades and
to blazon the flight of trailer shells. There are many other pyrophoric
(light-producing) alloys, including steel, which our ancestors used with
flint before matches and percussion caps were invented.

There are more than fifty metals known and not half of them have come
into common use, so there is still plenty of room for the expansion of
the science of metallurgy. If the reader has not forgotten his
arithmetic of permutations he can calculate how many different alloys
may be formed by varying the combinations and proportions of these
fifty. We have seen how quickly elements formerly known only to
chemists--and to some of them known only by name--have become
indispensable in our daily life. Any one of those still unutilized may
be found to have peculiar properties that fit it for filling a long
unfelt want in modern civilization.

Who, for instance, will find a use for gallium, the metal of France? It
was described in 1869 by Mendeleef in advance of its advent and has been
known in person since 1875, but has not yet been set to work. It is
such a remarkable metal that it must be good for something. If you saw
it in a museum case on a cold day you might take it to be a piece of
aluminum, but if the curator let you hold it in your hand--which he
won't--it would melt and run over the floor like mercury. The melting
point is 87 deg. Fahr. It might be used in thermometers for measuring
temperatures above the boiling point of mercury were it not for the
peculiar fact that gallium wets glass so it sticks to the side of the
tube instead of forming a clear convex curve on top like mercury.

Then there is columbium, the American metal. It is strange that an
element named after Columbia should prove so impractical. Columbium is a
metal closely resembling tantalum and tantalum found a use as electric
light filaments. A columbium lamp should appeal to our patriotism.

The so-called "rare elements" are really abundant enough considering the
earth's crust as a whole, though they are so thinly scattered that they
are usually overlooked and hard to extract. But whenever one of them is
found valuable it is soon